This invention relates generally to circuits and signal connectors supporting RS-232 communication protocol, and more particularly to a DB9 circuit and connecting cable, and signal pin mapping for supporting RS-232 communications in a disk drive controller environment.
The computer industry is marked by rapid advancement in hardware, firmware, software, and architectures generally. Because of the widespread proliferation of computers and the need for rapid and reliable access to data, computer data storage technology is at the forefront of such changes. In order to provide rapid and reliable access to large amounts of data, for example for commercial databases, hotel or airline reservation systems, corporate records, and the like, systems of related disk drives, such as Redundant Arrays of Independent Disks (RAID) systems are frequently and increasingly used. RAID refers to Redundant Array of Independent Disks, a firmware/hardware implementation of a disk array controller in which data is stored on disks in such a manner as to improve performance and avoid data loss in the presence of a disk failure. For these multiple disk configurations, there is frequently a need for multiple controllers (in various configurations), multiple disk drives (with different capacities and different vendor or revision), and the need to swap devices and/or controllers in a disk array system in the event of up sizing storage capacity or replacing a failed device. In addition, there may be a desire to upgrade certain components with newer versions providing advanced features, but at the same time to retain other components for a reasonable lifetime. These issues create a need for some flexibility and adaptability in device-to-device communications, whether the devices are disk drives, other memory storage devices, disk drive controllers, host computer systems, communication systems, or the like.
Increasingly, a hardware device designed for one purpose could desirably be adopted for another purpose so as to maintain that device in the modified or upgraded system configuration, or to increase its capabilities on some manner. For example, in many commercial RAID storage systems, the SCA connector is standardized so as to permit interchangability in the industry between devices made by different manufacturers. This standardization may occasionally restrict the ability of a particular vendor from implementing proprietary structures or using proprietary methods in connection with the devices. In this event, the ability to configure a standard device or a connector associated with a standard device in a non-standard way is valuable. Providing an ability to use an existing connector having a limited number of wires for another purpose may also allow upgraded features to be provided without replacing hardware, for example, without replacing entire printed circuit boards.
Therefore there is a need for electrical cable adaptors and circuits that remap a connector and its associated signals to another signal set. As both DB-9 and RS-232 interfaces are in common use for communication among different computer components, there is a particular need for means that permits a single DB-9 connector and its associated signals to be remapped to provide a standard RS-232 interface, particularly as such communication applies to an interface to a RAID controller in a single RAID controller system, or to provide a controller-to-controller communications link for messaging, control and status signals between two RAID controllers in a dual-active system.
These and other features and advantages are provided by the inventive structure and method.
The invention provides structure, including circuits, cabling, and computer architecture, and method for permitting a single DB-9 connector and its associated signals to be remapped to provide a standard RS-232 interface, particularly as such communication applies to an interface to a RAID controller in a single RAID controller system,, and to provide a controller-to-controller communications link for messaging, control and status signals between two RAID controllers in a dual-active system. While specific circuit and cable implementation embodiments are disclosed, the inventive concept and method may be more widely applied to a variety of standard and non-standard interfaces.